RS54695B1 - HEATED PANEL PANEL - Google Patents

Abstract

Panel (500A, 500B, 600A, 600B, 800, 900) with an outer surface (549, 949) adapted to be connected to the supporting frame and an inner surface (545, 945) adapted to define the boundaries of the compartment, where the panel comprises: a core (528A) , 528B, 928) located within the frame of the panel, where the core has its first and second surfaces, and its circumference, where the first 540, 940) and second (542, 942) surface layers are joined to the first and second surfaces of the core; one or more end elements (536) arranged between the surface layers (540, 542, 940, 942) and around the circumference of the core (528A, 528B, 928), with one or more end elements (536) joined to the first (540, 940) and another (542, 942) surface layer; element (504A, 504B, 704, 804, 904) for heating performed directly to the inner surface (545, 945) of the panel, characterized in that: the panel frame is made of reinforced phenolic material; having a carbon fiber material extending between two opposite electric lines (512A, 512B, 512B ', 812, 912) electrically interconnecting them; having an electrical conductor (516, 520A, 520B, 820, 920) coupled to each of the electrical lines of the heating element (504A, 504B, 804, 904) to supply voltage to the heating element; that the power lines (512A, 512B, 512B ', 812, 912) have a thickness greater than the thickness of the carbon fiber material and that the power lines are accepted in recessed pockets (552, 554, 556) of one or more end members (536). contains 13 more claims.

Description

TECHNICAL FIELD

This invention relates generally to heated panels, and more specifically to heated panels suitable for use in vehicles such as subway cars, high-speed vehicles, rail vehicles, buses, emergency vehicles, marine vehicles, semi-trailers, box trucks, elevator cabs, etc. Document JP2010/14076 describes a panel intended for underfloor heating where the panel is produced by a simplified production process.

BRIEF DESCRIPTION OF THE DRAFT PICTURES

Figure 1 represents a perspective view of the heated panel according to one version of the production;

Figure 2 represents a perspective view of the heated panel according to another variant of production;

Figure 3 represents a view of the disassembled assembly of the heated panels from Figures 1 and 2, which can be made together;

Figure 4 is a detailed view of the recessed pockets made on one of the heated panels shown in Figure 3;

Figure 5 is a perspective view of the identically fabricated heated panels of Figures 1 and 2, with the first surface layer removed to illustrate the heating elements;

Figure 6 is a cross-section of the final electrical block of the heated panel of Figure 1 taken along line 6-6 of Figure 1;

Figure 7 is a cross-section of the hollow conductor armature taken along line 7-7 of Figure 2;

Figure 8 is a schematic diagram illustrating the heating elements of the heated panel of Figures 1 and 2 coupled to a voltage source;

Figure 9 is a schematic view of the panel arrangement illustrating the assembly of several series-connected heating elements of the first type made of carbon fibers and applied in the heated panel.

Figure 10 is a schematic diagram of a panel arrangement illustrating a plurality of series-connected heating elements of another type made of carbon fiber and applied in a heated panel.

Figure 11 is an exploded view of the heated panel assembly where the heating elements form the core.

Fig. 12 is a top view of a heating element made of diamond-woven carbon fibers;

Figure 13 is a perspective view of a heating element made of carbon fiber film; and

Figure 14 is a cross-sectional view of the heating element made of the carbon fiber film of Figure 13 bonded to the outer surface of the first layer of the composite panel.

DETAILED DESCRIPTION

Before giving a detailed description of any of the embodiments of the invention, it should be understood that the application of the invention is not limited solely to the constructional details and components of the embodiments described below or illustrated in the accompanying drawings. The invention can also be implemented in other configurations and implementations.

Figures 1 through 7 show heated panels 500A, 500B. Each of the heated panels 500A, 500B is a composite panel and may be manufactured by the process described in US Patent No. 6,824,851 or a similar process. Nevertheless, each of the panels 500A, 500B further contains a heated layer within itself as described below.

Referring to Figures 1 and 2 each of the heated panels 500A, 500B includes a respective pair of heating elements 504A, 504B covering a major portion of the surface of each panel. Each of the heating elements 504A, 504B may contain a resistive heating element such as a braided sheet 508A, 508B containing a plurality of threads made of carbon fibers extending between two oppositely derived electrical lines (electrical line 512A of the first heating element 504A and electrical line 512B of the second heating element 504B). The way the carbon fibers forming the sheets 508A, 508B are woven can be a standard weaving pattern (a so-called "basket weave" pattern) with one set of threads running parallel to the electrical leads 512A, 512B, 512B\ and another set of threads twisted at right angles to the threads of the first set, but other ways of weaving the fibers can be used. Sheets 508A, 508B may be made as flexible sheets made from raw carbon fiber material (ie, unstructured or pre-reinforced material rather than made from rigid carbon fiber panels), or alternatively sheets 508A, 508B may be made as structured and preformed carbon fiber sheets.

Sheets 508A, 508B may be made of any of the various types of carbon fiber filaments so that each of the heating elements 504A, 504B has an electrical resistance corresponding to the mass per unit area of the sheet. The size and/or type of carbon fiber filaments in the braided sheets 508A, 508B can be selected from a number of available sizes and types based on mass per unit area and in order to achieve the desired electrical resistance required for a particular application. For example, the first sheet 508A may be made of coarse-knit carbon fibers and have a weight per unit area between about 280 g/m<2> and 320 g/m<2>, while the second sheet 508B may be made of fine-knit fibers and have a weight per unit area between 180 g/m<2> and 220 g/m<2>. According to one manufacturing method, sheet 508A is made of coarse-woven carbon fibers with a weight per unit area of approximately 295 g/m<2>, while another sheet 508B is made of fine-woven carbon fibers with a weight per unit area of approximately 192 g/m<2>. However, other types of woven carbon fiber sheets with other masses per unit area may be used to achieve the desired result in heating elements 504A, 504B. Furthermore, the carbon fibers can also exist in various forms including various knitted or non-woven forms as described in more detail below, in order to obtain a resistive heating element.

Each of the electrical leads 512A, 512B of each of the heating elements 504A, 504B may be made of two sheets or rods made of an electrically conductive material, such as copper, which include and clamp the edge of the carbon fiber sheet and which are fastened together. The sheets or rod forming each of the electrical leads 512A, 512B may be coupled with mechanical fasteners (eg, screws, threads, and the like) or alternatively may be joined by other means (eg, welding, brazing, gluing, etc.). As shown in Figure 1, the heating elements 504A of the first heated panel 500A are electrically series-coupled with one of the lines 512A of each of the heating elements 504A by a conductor 516. As shown in Figure 2, the heating elements 504B of the second heated panel 500 are electrically series-coupled by using one of the electric lines 512B' as a common electric line for both elements 504B for heating until one electrical line 512B on each of the heating elements 504B is not shared with another heating element 504B. Each of the heated panels 500A, 500B further includes a pair of wires or electrical conductors 520A, 520B that allow each of the panels 500A, 500B (and heating elements 504A, 504B within them) to be coupled to an external voltage source. In the first panel 500A, one of the two conductors 520A is coupled to each of the two electrical lines 512A that are not directly coupled by the connecting conductor 516. In the second panel 500B, one of the two conductors 520B is coupled to the unique (non-shared) electrical line 512B of each of the heating elements 504B. If required (for example to achieve the desired total electrical resistance to achieve the correct thermal performance or to maintain the function of one heating element when the other fails), the two heating elements 504A for the first panel 500A or the two heating elements 504B for the second panel 500B can alternatively be connected in parallel instead of in series. It is also necessary to emphasize that any of the heated panels 500A, 500B can be performed with one heating element or with more than two heating elements in order to cover a predetermined surface of the panel 500A, 500B which may or may not represent the majority of the surface, which depends on the specific installation variant.

Another feature that separates the heated panels 500A, 500B from Figures 1 and 2 is that the electrical leads 512A of the first heating element 504A are run along the shorter edges of the rectangular carbon fiber sheet 508A, while the electrical lines 512B, 512B' of the second heating element 504B are run along the longer edges of the rectangular carbon fiber sheet 508B. fibers. This illustrates another way, which is independent of the size of the carbon fiber strands or of the variation in the way the fibers are woven, by which the change in electrical resistance (and thermal power for a given applied voltage) of the heating elements 504A, 504B can be effected without changing the area of the carbon fiber sheets 508A, 508B since the electrical resistance varies proportionally with length and inversely proportional with cross-sectional area. This provides a degree of modularization to the overall solution by providing heating elements that are of one size and which can provide different heat outputs as needed in different installation designs, or alternatively this allows heating elements of the same size to be coupled to different voltage sources and produce similar or the same amounts of heat. Furthermore, this promotes flexibility in designing multi-panel floor structures, for example, those where a number of heated panels can be coupled together and/or coupled to the same voltage source.

Looking at Figures 3 to 5, the construction of panels 500A, 500B will be described in more detail. it is not necessary, as shown at least in Figures 3 and 5, the two panels 500A, 500B of Figures 1 and 2 can be made identical. If it is necessary to separate panels 500A, 500B, it is possible to form a cut along line 524 after panels 500A, 500B are fully cured. Each of the panels 500A, 500B includes a lightweight core 528A, 528B that is made of a low-density material that is highly compressed (eg, foam, balsa wood, plywood, reinforced materials, or any combination thereof). According to one embodiment, the cores 528A, 528B are formed and pre-dried and cured reinforced cores made in the manner described in US Patent No. 6,824,851 to contain a plurality of alternating strips 530 of foam and ribs 532 of pre-cured phenolic resin. A plurality of end members 536 are positioned immediately adjacent to or around each of the cores 528A, 528B to define the perimeter of each of the panels 500A, 500B. Some of the end members 536 are coupled to the respective cores 528A, 528B to directly embrace them along their circumference. However, as shown in Figures 3 and 5, each of the panels 500A, 500B may optionally be segmented to contain a plurality of cores 528A, 528B such that some of the end members 536 may represent "interior" end members 536 that do not define the perimeter of the panels 500A, 500B. The end members 536 may be made of a higher density material than the cores 528A, 528B such as machinable blocks of reinforced phenolic material as described in US Patent No. 6,824,851. Like the cores 528A, 528B, the end members 536 are formed and cured before the drying of the pair of surface layers 540, 542 comprising the cores 528A, 528B and the end members 536 is complete.

The cores 528A, 528B and end members 536 are sandwiched between the first surface layer 540 and the second surface layer 542. If the two panels 500A, 500B are made identically, as shown, the surface layers 540, 542 are common to both panels 500A, 500B (until the finished panels 500A, 500B are finally separated by cutting). The first surface layer 540 includes a surface 544 that faces the cores 528A, 528B and a counter surface 545 that faces away from the cores 528A, 528B and defines one side, the inner face of the panel 500A, 500B. The second surface layer 542 includes a surface 548 that faces the cores 528A, 528B and a counter surface 549 that faces the opposite of the cores 528A, 528B and defines the other side, the outer face of the panel 500A, 500B. The core-facing surfaces 544, 548 of the first and second surface layers 540, 542 are joined to the cores 528A, 528B and end members 536 forming a closed panel boundary that prevents unwanted ingress of foreign material, such as water, into the interior and cores 528A, 528B of panels 500A, 500B. The outer side 545 of the first surface layer 540 may define the inner surface of the panel 500A, 500B to form the inner boundary of the compartment (for example, the floor of a vehicle such as a car, bus, elevator car, etc.), and the outer surface 549 of the long surface layer 542 may define the outer surface of the panel 500A, 500B facing the supporting structure or frame that defines or surrounds the compartment. The surface layers 540, 542 in some variants of production can be made of reinforced phenolic resin (for example, of phenolic resin reinforced with fiberglass).

As best shown in Figure 4, some of the end members 536 may include recessed pockets 552, 554, 556 intended to receive portions of the heating elements 504A, 504B and associated wiring. For example, a first set of recessed pockets 552 are formed in certain end members 536 to receive each of the electrical leads 512A, 512B, 512B'. Each of the recessed pockets 552 has a planar shape/area and depth corresponding to the shape/area and depth of the respective electrical leads 512A, 512B, 512B'. Therefore, the electrical conduits 512A, 512B, 512B' do not require any significant increase in the overall thickness of the panels 500A, 500B compared to non-heated panels. Therefore, the set of manufacturing tools does not need to be specialized and can be easily converted by the end user between heated and non-heated panel manufacturing applications. For example, heated panels 500A, 500B may have an overall thickness of approximately 19 millimeters (0.75 inches) which is equivalent to the standard overall thickness of conventional panels in certain industrial areas, such as non-heated floor panels. The carbon fiber sheets 508A, 508B may have a thickness that is significantly less than the thickness of the electrical leads 512A, 512B, 512B' and, therefore, the carbon fiber sheets 508A, 508B need not be made with indentations to avoid significantly increasing or distorting the overall thickness of the panel. For example, the carbon fiber sheets 508A, 508B may have a thickness of approximately 0.254 millimeters (0.10 inches). If the carbon fiber sheets 508A, 508B possess a thickness significant enough to require countermeasures, the carbon fiber sheets 508A, 508B may be positioned solely over the cores 528A, 528B which may have a reduced thickness compared to the end members 536. The difference in thickness between the cores 528A, 528B and the end members 536 may be approximately equal to the thickness of the carbon fiber sheets 508A, 508B so as to form a substantially uniform, flat surface for receiving the core facing surface 544 of the first surface layer 540.

In addition to recessed pockets 552 for electrical leads 512A, 512B, 512B', recessed pockets or channels 554 are formed in certain end members 536 to accept electrical wiring coupled to heating elements 504A, 504B, such as connecting conductor 516 and conductors 520A, 520B. Similar to the recessed pockets 552 intended to receive electrical leads 512A, 512B, 512B', the recessed channel pockets 554 prevent the overall thickness of the panel from increasing or deforming due to the various electrical conductors 516, 520A, 520B.

Referring in particular to Figures 4 through 6, additional recessed pockets 556 are provided in certain terminal elements 536. The recessed pockets 556 are shaped to receive electrically conductive terminal blocks 560. The terminal blocks 560 are formed on each of the leads 520A of the first heating element 504A in the illustrated embodiment and in some construction variants may be made of a piece of pure copper. The end blocks 560 are fully recessed into the recessed pockets 556 to prevent the overall panel thickness from increasing or deforming. As shown in Fig. 6, a connection terminal 564 (eg, in the illustrated embodiment in the form of a screw) may be coupled to each of the end blocks 560 to provide a means of connecting the heating elements 504A to a voltage source. In the illustrated embodiment, each of the connection terminals 564 is screwed into formed threaded holes provided in the respective end blocks 560, while the connection terminal 564 is shaped to pass through an opening 566 in the second surface layer 542 to extend outside the panel 500A. easily, the end block 560 is shown with a thickness equivalent to that of the end members 536, the end block 560 may have a reduced thickness (eg, approximately equal to half or a quarter of the thickness of the end member 536), and in such embodiments, the end block 560 may be positioned immediately next to the second surface layer 542, with an additional end block positioned above it, or the recessed pockets 556 may be designed to have a substantially smaller depth. equal to the thickness of the end blocks 560. The hole 566 can be drilled after the panel 500A has fully cured. Panel 500A may alternatively be implemented with any desired type of connector or fitting necessary to couple the heating elements 504A to an external voltage source, readily not shown, another panel 500B may have a similar implementation.

Figure 7 shows an alternative means of providing an electrical connection between the heating elements 504B and an external voltage source. In the embodiment of Figure 7, the electrical conductors 520B have the necessary length to extend beyond the panel 500B. In order to allow the passage of the conductors 520B outward from the panel 500B, the hollow armature 570 is coupled to the outwardly facing surface 549 of the second surface layer 542 at a position 572 where the electrical conductors 520B pass through the second surface layer 542. The position 572 where each of the electrical conductors 520B passes through the second surface layer 542 may be in communication with one of recessed wiring channels 554 that may be directly formed within recessed pockets 552 that accommodate electrical leads 512B, 512B'. In the version shown, the hollow armature 570 forms the so-called 90 degree "elbow" that may be adhesively bonded to the second surface layer 542, although other means of joining such as mechanical joining elements may be used. In the shown embodiment, the hollow armature 570 contains a flange 574 designed for direct coupling with the outer surface of the panel 500A provided by the surface 549 of the second surface layer 542. Not shown, the first panel 500A may have a similar design.

It should be noted that the layers shown on the cross-sections from Figures 6 and 7 can in practice be realized on a different scale compared to the one shown here, which represents only one possible scheme of layers. For example, each of the carbon fiber sheets 508A, 508B is shown to occupy a discrete and substantial space between the cores 528A, 528B and the first surface layer 540. However, the carbon fiber sheets 508A, 508B may in practice be significantly thinner than the first surface layer 540. Further, the carbon fiber sheets 508A, 508B need not necessarily be positioned between the core 528A, 528B and the core-facing surface 544 of the first surface layer 540, may already be incorporated into the first surface layer 540 so as to be located between the two surfaces 544, 545 of the first surface layer 540 by coating the sheets 508A, 508B with a liquid resin (for example, a phenolic resin reinforced with fiberglass) which after hardens and forms a solid surface layer 540 of resin within which are carbon fiber sheets 508A, 508B. In such an embodiment, the manufacturing process may include applying a first layer of liquid phenolic resin over the surface of the cores 528A, 528B which are intended to receive the first surface layer 540, placing sheets 508A, 508B of carbon fiber heating elements 504A, 504B into the first layer of liquid phenolic resin, and finally applying a second layer of liquid phenolic resin to the sheets 508A, 508B carbon fiber. One or more reinforcing layers (eg, a fiberglass backing) may also be placed over or under the carbon fiber sheets 508A, 508B and then impregnated with a liquid phenolic resin. After the liquid phenolic resin is cured (eg by heat and pressure), a unitary surface layer 540 is formed to include carbon fiber sheets 508A, 508B between its surfaces 544, 545. The liquid phenolic resin of the first and second surface layers 540, 542 also forms a strong bond with the phenolic ribs 532 of the cores 528A, 528B during the drying and curing process so that the various layers are united into one solid composite structure of the resulting panel. It is possible to apply alternative variants of production in order to position elements 504A, 504B for heating. For example, the heating elements 504A, 504B (and in particular the carbon fiber sheets 508A, 508B) may also be provided on the joining surfaces of the panels 500A, 500B such as on the surface 545 of the first surface layer 540, and may be applied to the first surface layer 540 after it has been cured and formed. Regardless of whether they are located above, below, or within the first surface layer 540 and regardless of whether they are performed before or after the formation and curing of the first surface layer 540, all of the aforementioned examples of specific positions of the heating elements 504A, 504B imply that the heating elements 504A, 504B are positioned immediately next to the inner surface 545 of the panels 500A, 500B in order to enabled efficient heating of the inner side of panels 500A, 500B.

An electrical diagram showing the heating elements 504A, 504B of the respective panels 500A, 500B is shown in Fig. 8. For ease of understanding in Fig. 8, the panels 500A, 500B are shown together, they can be separated from each other by a cut along the line 524 to allow them to be placed separately in the aforementioned manner. Each of the elements 504A for heating the first panel 500A is shown schematically in the form of resistance R1, and also each of the elements 504B for heating the second panel 500B is shown schematically in the form of resistance R2. It is shown that similar voltage sources are applied to each of the sets of heating elements 504A, 504B with a first voltage V. If the resistance R1 of each first heating element 504A and the resistance R2 of each second heating element 504B are substantially equivalent, then a substantially equivalent current will flow through each set of heating elements 504A, 504B and substantially equivalent heating will be provided to each panel. 500A, 500B. However, the resistances R1, R2 are different in some construction variants due to at least one of the following factors: the type of material from which the sheets 508A, 508B are made and the physical execution of each of the sheets 508A, 508B between the respective electrical lines, where both factors can lead to a change in resistance and current strength, and therefore to a change in thermal power.

As shown in the Figures, the heating elements 504A, 504B cover most of the surface of the panel, but not the entire surface thereof. However, in addition to this, it is necessary to aim for practically any desired configuration in terms of the required thermal density and the heated area of the specific panel. For example, some panels may only have certain areas that define a heated passenger compartment, for example, so that heating is only applied to those specific areas of the panel. According to other manufacturing variants, the size of the heating elements 504A, 504B may be substantially equal to the entire surface of the panel 500A, 500B. According to additional embodiments, the first surface layer 540 can achieve a substantially uniform elevated temperature on the inner surface 545 even when the elements 504A, 504B do not cover the entire surface of the panel.

Figures 9 and 10 schematically show variants of panels 600A, 600B that use more than two heating elements 504A, 504B. Figure 9 shows a panel 600A that is generally T-shaped and has three heating elements 504A arranged to cover most of the surface of the panel 600A. The panel 600A may have the basic construction described above. As with the panel 500A of Figure 1, the heating elements 504A contain electrical leads 512A arranged along each of the shorter dimensions of the rectangular panels. of carbon fiber sheets 508A. The three heating elements 504A are connected in series between adjacent electrical leads 512A. The panel 600B of Figure 10 is substantially identical to the panel 600A of Figure 9. As is the case with the heating elements 500B of Figure 2 contain electrical lines 512B run along each of the larger dimensions of the rectangular carbon fiber sheets 508B. Three heating elements 504B are connected in series by connecting conductors 516 between adjacent electrical leads 512B. The central heating element 504A, 504B in each of the panels 600A, 600B has a rotational orientation that is offset by 90 degrees relative to the two remaining heating elements 504A, 504B in each of the panels 600A, 600B.

As shown by the difference in thickness of the lines of Figures 9 and 10, the carbon fiber sheets 508A in the first panel 600A are formed of coarser or heavier carbon fibers than the sheets 508B in the second panel 600B. Therefore, the carbon fibers of the first sheet of 508A have a significantly lower electrical resistance. However, because the two electrical lines 512B of each of the second heating elements 504B are placed closer to each other than the electrical lines 512A of each of the first heating elements 504A, the total resistance of each of the elements 504B of the second panel 600B can be substantially equivalent to the total resistance of each of the heating elements 504A of the first panel 600A. In order to provide a heating element with a lower electrical resistance compared to the resistance of the shown heating elements 504A, 504B, it is necessary to use coarser carbon fibers such as those used to make sheets 508A using the wiring configuration shown in Figure 10. In order to provide a heating element with a higher electrical resistance compared to the resistance of the shown heating elements 504A, 504B, it is necessary to use a finer carbon fibers such as those used to make sheets 508B using the wiring configuration shown in Figure 9. Options for performing and making one or more heated panels may further include providing one or more of any of the described heating elements in one panel, or in multiple electrically connected panels and connecting the different heating elements and different panels in parallel or series with one or more voltage sources. Figure 11 shows another heated panel 700 which does not represent a variant embodiment of the invention, but is presented here as a useful example in order to understand the invention.

The panel includes a first surface layer 740, a second surface layer 742, and a plurality of end members 736, all of which may be substantially similar to the respective previously described features of the panels 500A, 500B. Panel 700 includes a heating element 704 similar to the previously described heating element 504B, but other variations of heating element 704 are certainly conceivable. In the illustrated embodiment, the heating element 704 comprises a woven carbon fiber sheet 708 extending between two opposed electrical leads 712 each having an electrical conductor 720 extending to connect them to a voltage source (not shown). As described in connection with the electrical leads 512A, 512B, 512B' of the panel 500A, 500B, the electrical leads 712 have a thickness that is significantly greater than the thickness of the carbon fiber sheet 708. Instead of having recessed pockets designed to receive electrical leads 712, panel 700 does not have any conventional core but rather a pair of auxiliary reinforcement layers 787 (eg, a fiberglass backing) placed above and below carbon fiber sheet 708, but not over electrical leads 712 to provide flush sides for bearing surfaces 744, 748 of first and second surface layers 740, 742. In the embodiment of Figure 11, the total thickness of panel 700 between surfaces 745, 749 of the outer layers may be significantly less than the thickness of panels 500A, 500B (for example, about 6.35 millimeters (0.25 inches) compared to about 19 millimeters (0.75 inches)). Compared to conventional cores, the panel 700 may be considered coreless, but the heating element 704 and auxiliary reinforcement layers 787 may also be considered the panel core. As is the case with the termination elements 536 described above, the termination elements 736 of the panel 700 may include recessed channels 754 for receiving electrical leads 720, and/or recessed pockets 756 for receiving electrical termination blocks (not shown).

Figure 12 shows the heating element 804 with a different construction compared to the heating elements 504A, 504B, 704 described above. In contrast to the 90 degree carbon fiber braiding method in which one set of strands is parallel to the electrical lines while the other set of strands is orthogonal to the electrical lines, the sheet 808 of the heating element 804 of Figure 12 is a diamond weave formation in which all the carbon fiber strands are crossed at 45 degree angles to the electrical lines 812. As is the case with other heating elements that are previously described, the heating element 804 includes an electrical conductor 820 extending from each electrical lead 812 to enable its connection to an external voltage source, easily Figure 12 shows one possible embodiment, it should be understood that it is possible to use other types of carbon fiber weave that may or may not be diamond shaped.

Figure 13 shows another type of heating element 904 intended for use in the manufacture of heated panels 900 (Figure 14). The heating element 904 includes a membrane or film 908 made of resistive carbon fiber rather than a woven carbon fiber sheet. The carbon fiber film 908 may be a composite film such as a thin, closed and fiber-reinforced PET film with integral electrical leads 912 made of copper. The carbon fiber film 908 may have a thickness of less than approximately 0.5 mm. The film 908 may also be made with a greater number of openings or perforations 913. The film 908 of Figure 13 may easily be incorporated into a composite panel in a manner similar to that described above, Figure 14 shows one particularly unique means of constructing a heated composite panel 900.

Similar to the other previously described panels, panel 900 includes first and second surface layers 940, 942 with a core 928 (which is, for example, made of strips 930 of foam and ribs 932 of cured phenolic resin) formed between them. However, Figure 14 shows that the heating element 904 can be positioned on the surface 945 of the first surface layer 940 opposite the surface 944 facing the core. In some embodiments, the heating element 904 may be bonded to the surface 945 of the first surface layer 940 by adhesive 951. Therefore, the heating element 904 forms the outer surface of the panel 900 as a whole. The surface 945 of the first surface layer 940 that receives the heating element 904 may be the inner surface of the panel 900 used to define the inner boundary of the compartment. In order to cover the heating element 904 and prevent it from being damaged by walking on it or otherwise, additional covering such as floor coverings 999 can be placed over the panel 900.

As briefly noted above, a plurality of heated composite panels according to any of the embodiments described herein may be applied together to form the floor structure of a vehicle such as a train, bus, elevator car, and the like. The heating elements that are implemented in each of a plurality of heated panels or in a designated group of heated panels can be mutually connected in parallel or in series with a common voltage source. Each heated panel or group of heated panels may also be coupled to unique voltage sources that may provide substantially equivalent voltages, different voltages, or adjustable voltages.

Various features and improvements achieved by the invention are set forth in the following Claims.

Claims (14)

1. A panel (500A, 500B, 600A, 600B, 800, 900) having an outer surface (549, 949) adapted to connect to a supporting frame and an inner surface (545, 945) adapted to define compartment boundaries, the panel comprising: a core (528A, 528B, 928) located within a panel frame, where the core has its first and second surfaces, and its circumference, where the first (540, 940) and second (542, 942) surface layers are joined to the first and second surfaces of the core; one or more end members (536) disposed between the surface layers (540, 542, 940, 942) and around the circumference of the core (528A, 528B, 928), with one or more end members (536) bonded to the first (540, 940) and second (542, 942) surface layers; element (504A, 504B, 704, 804, 904) for heating carried directly to the inner surface (545, 945) of the panel; indicated thereby. As the panel frame is made of reinforced phenolic material; that the heating element comprises a carbon fiber material extending between two opposite electrical leads (512A, 512B, 512B', 812, 912) electrically coupling them; having an electrical conductor (516, 520A, 520B, 820, 920) coupled to each of the electrical leads of the heating element (504A, 504B, 804, 904) to supply voltage to the heating element; wherein the electrical conduits (512A, 512B, 512B', 812, 912) have a thickness greater than the thickness of the carbon fiber material and wherein the electrical conduits are received in the recessed pockets (552, 554, 556) of one or more end members (536). 2. The panel of Claim 1, wherein the carbon fiber material comprises a plurality of carbon fiber strands interwoven in a diamond shape or to form a perforated film, and wherein each of the electrical leads (512A, 512B, 512B', 812, 912) may comprise a pair of copper plates comprising a respective end of the carbon fiber material. 3. The panel of Claim 1, wherein the heated element (504A, 504B, 804, 904) is incorporated into the first surface layer (540, 940) of the panel and integrally bonded thereto by means of a reinforced phenolic material. 4. The panel of claim 4, wherein the electrical conductors (516, 520A, 520B, 820, 920) are provided in the recessed pockets of the one or more end members, and wherein the one or more recessed pocket end members may be machined phenolic blocks. 5. The panel of Claim 1, wherein each of the electrical conductors (516, 520A, 520B, 820, 920) terminates in a corresponding electrically conductive termination block (560) which is received in a corresponding recessed pocket (552, 554, 556) provided in one or more termination elements (536), wherein a connection terminal (564) is provided in each of the terminations. blocks (560) and extends beyond the panel to connect the heating element (504A, 504B, 804, 904) to the voltage source, and where one or more end elements having recessed pockets (552, 554, 556) may be machined phenolic blocks. 6. The panel according to Claim 1, further comprising a pair of hollow armatures (570) coupled to the outer surface of the panel, wherein each of the hollow armatures forms a passage through which a respective electrical conductor (516, 520A, 520B, 820, 920) passes and extends away from the outer surface (549, 949) for connection to a voltage source. 7. The panel of Claim 1, wherein the heating element (504A, 804, 904) is a first heating element, wherein the panel further comprises at least one additional heating element (504B) connected in series with the first heating element, and wherein the first heating element and the at least one additional heating element may have substantially equivalent surface area and may provide a plurality of uniformly heated areas within the panel. 8. The panel according to Claim 7, wherein each of the first elements (504A, 504B, 804, 904) and at least one of the additional heating elements (504B) has a longer dimension and a shorter dimension, and where the electric lines (512A, 512B, 512B', 812, 912) are arranged along the longer dimensions, and where each of the first heated elements and at least one additional heating element the heated element may have a longer dimension and a shorter dimension, and where electrical lines may be run along the shorter dimension. 9. A process for manufacturing a heated composite panel (500A, 500B, 600A, 600B, 800, 900), where the process includes: providing a core {528A, 528B, 928); positioning the end members (536) around the core so that they surround it and define the perimeter of the panel, where the end members have a density greater than the core density and contain a number of recessed pockets (552, 554, 556); providing a heating element (504A, 504B, 804, 904) comprising a carbon fiber sheet extending between two opposite electrical leads (512A, 512B, 512B', 812, 912); placing the heating element on the core such that the electrical leads are received in at least one of the plurality of recessed pockets and such that the carbon fiber sheet extends over at least a portion of the core (528A, 528B, 928); and enclosing the core and end members between the first reinforced phenolic surface layer (540, 940) and the second reinforced phenolic surface layer (542, 942) to enclose the core and to enclose and embed the carbon fiber heating element within the panel. 10. The method of claim 9, further comprising embedding the carbon fiber heating element (504A, 504B, 804, 904) within the first reinforced phenolic surface layer (540, 940) by immersing the carbon fiber heating element (504A, 504B, 804, 904) in at least one layer of liquid phenolic resin, placing a layer for reinforcing over the carbon fiber heating element, coating the reinforcing layer with at least one additional layer of liquid phenolic resin, and drying and curing all layers of liquid phenolic resin together to form a first reinforced surface phenolic layer with embedded carbon fiber heating elements, and wherein the end elements (536) may be in the form of phenolic blocks, and wherein the process may include forming at least one recessed pocket (552, 554, 556) in phenolic blocks by machine processing, 11. The method of claim 9, further comprising providing a pair of electrical conductors (516, 520A, 520B, 820, 920) coupled to electrical conduits (512A, 512B, 512B', 812, 912) for connecting the heating elements to a voltage source and placing each pair of electrical conductors in one of a plurality of recessed pockets. (552, 554, 556). 12. The method of Claim 11, further comprising providing end members such as phenolic blocks and forming at least one recessed pocket (552, 554, 556) in the phenolic blocks by machining them. 13. The method of Claim 11, further comprising coupling each of the pairs of conductors (516, 520A, 520B, 820, 920) to an electrically conductive terminal block (560), and placing each of the electrically conductive terminal blocks (560) in one of a plurality of recessed pockets (552, 554, 556), and which may further comprise coupling a connection terminal (564) with each of the electrically conductive terminal blocks in such a manner that terminal blocks (564) may extend beyond the panel to connect the carbon fiber heating element to a voltage source. 14. The method of Claim 9, wherein the heating element is a first heating element (504A, 804, 904), wherein the method further comprises providing a second similar heating element (504B), and positioning the first and second heating elements in a non-overlapping manner above the core (528A, 528B, 928), and may further comprise electrically connecting the first and second heating elements in series.